Africa's most extravagant oil producer has long had the money, minerals, and raw demographics to dominate its region like a bull in what might otherwise be France's backyard or the People's Republic of China's shop.

The nation's 154 million people account for more than half of West Africa's population, and one-seventh of Africa's total head count. Its gross domestic product is growing as fast as any world economy left of China.

The only thing Africa's sleeping giant has lacked – or, at least, the main thing – is credibility. When, for example, President Obama made his first trip to Africa as president, he publicly snubbed Nigeria to visit famously democratic Ghana, a fellow ex-British colony with a tenth of Nigeria's population and an even smaller fraction of its oil.

Yet Nigeria's battered international reputation appears on the mend following Saturday's presidential election – Nigeria's only free and fair election since it moved away from military rule 12 years ago.

International observers judged the poll reasonably fair, a marked improvement on the 2007 vote that was universally denounced as an descent into election theater.

"This is such an important moment," said Alex Vines, Africa analyst for the London-based watchgroup Chatham House. "Nigeria now has the legitimacy behind it of an election that met minimal international standards. It's very promising. It will allow Nigeria to speak more authoritatively when there are significant governance challenges in place like Guinea-Bissau."

The country is already there.

Nigeria's now duly elected president, Goodluck Jonathan, has been vocal in support of Guinea-Bissau's military reform program. Leaders of the former Portuguese colony are trying to retool their military to pave roads and dig irrigation canals, instead of smuggle Colombian cocaine toward Europe.

More audaciously, Nigeria stuck its boot in the middle of what may have been Africa's most divisive conflict since the fall of apartheid: Ivory Coast.

When the former French West African colony's defeated incumbent President Laurent Gbagbo refused to concede last November's elections, South African dignitaries flew thousands of miles over French-speaking terrain they rarely visit to offer Gbagbo a Zimbabwe-style powersharing deal that repulsed West African leaders.